What do child slavery in Ghana, Somali piracy and the illegal global ivory trade have in common? Their root causes can all be traced back to declining wildlife populations.

At least that's the theory of a group of researchers at the University of California, Berkeley, who looked at how wildlife loss impacts conflict in places where people depend on wildlife to survive.

Justin Brashares and his colleagues say that the way governments and international organizations respond to crimes like poaching often do not address the full "ecological, social and economic complexity of wildlife-related conflict."

"We thought it was critical to connect the dots" among disciplines, said Brashares, the lead author of a paper published recently in the journal Science.

The connection between the loss of wildlife and human populations has also been underemphasized in academia, said co-author Douglas McCauley, an ecologist currently at University of California, Santa Barbara, who took part in the study as a postdoctoral student at UC Berkeley.

While conservationists like McCauley focus most of their research on how to preserve species for their own sake, species preservation is also a vital consideration for human populations, he said.

Wildlife is an important economic driver around the world. The global harvest of marine and land animals is valued at $400 billion each year. About 15 percent of the world's population depends on wildlife to survive. Among the poorest people on the planet, meat from these animals is the main source of protein.

When disruptions to those populations happen, they can have devastating impacts on the stability of the people relying on wildlife for sustenance.

When fish lead to piracy
In Somalia, piracy off the country's coastline can be traced back to 1991, the year the country's government collapsed and international vessels began fishing there illegally. Because the country no longer had a coast guard to patrol its shores, Somali fishermen began attacking the international vessels.

Brashares said few of the academics and journalists he'd spoken to had known about the conflict's origins.

"We've really glorified [piracy] in a different way," Brashares said. "It really started as a battle for fish."

In Ghana, depleted fish populations have meant fishermen had to work harder to harvest a big enough catch. To reduce costs, fishermen have used forced child labor for dangerous tasks like mending underwater nets. Thousands of children are working in the fishing industry in Ghana, according to a 2012 report by the U.S. Department of Labor.

The effects of declining wildlife populations could be even worse when the impacts of climate change combine with overharvesting, potentially leading to an ecosystem collapse, Brashares said.

Rising temperatures have already affected people in northern Scandinavia who rely on reindeer for protein, and populations in northern Canada and Alaska who rely on seal meat, he said.

Climate change would not just affect wildlife but other food sources as well.

He said that ecologists and climate scientists have struggled in similar ways to connect the problems they are seeing with their impacts on society.

Where climate change triggers conflicts
"Really the most important consequence [of climate change] is going to be unrest and conflict between billions of people when their crops won't grow," said Brashares, envisioning a worst-case scenario.

In other cases, the rapid decline of certain species, like African elephants and rhinoceroses, has made them a desirable target for poachers.

"A lot of violent groups are trying to capitalize on declining species, and they are breeding violence as a result," McCauley said.

The Janjaweed, the Lord's Resistance Army, al-Shabab and Boko Haram have all used money from poached horns and tusks to fund terrorist attacks.

Limited supply and high demand have driven the price of ivory, made from elephant tusks, up to $3,000 per kilogram (roughly $1,400 per pound). Rhino horns are worth $60,000 per kilogram (about $27,300/lb) to $100,000 per kilogram (about $45,500/lb).

International organizations taking a tougher approach to punishing poaching do not address the factors that are driving demand for poaching in the first place, said the researchers.

Jorge Rios, the chief of the Sustainable Livelihood Unit of the United Nations Office on Drugs and Crime (UNODC), emphasized the importance of being tough on poaching. His program works with governments to create stricter penalties for poaching and trafficking wildlife, and helps enforce those laws.

Declining species not just a scientific concern
"Decreasing demand is one thing, but if you don't have appropriate legislation, then you are not going to stop the killing of these animals," he said. "People are finally waking up to the fact that poaching is a crime."

However, he agreed that in order to be effective, anti-poaching efforts must take a three-pronged approach that addresses demand for things like ivory and rhino tusks, the livelihood of the people involved, and enforcement of the law.

"If we don't provide people with livelihoods, if we don't change market dynamics, then we aren't going to win," Rios said.

There are a few international organizations that demonstrate the kind of interdisciplinary approach that Brashares and his colleagues envision. One of the closest examples may be the Intergovernmental Panel on Climate Change (IPCC), which includes a mix of policymakers, academics and government employees brought together to form multidisciplinary initiatives.

For such an organization to be successful, "they would need to have political clout if they are to get to the deeper causes of these social issues," he said. But "there isn't currently a platform to even approach these challenges," he added.

Critics say that issues of child exploitation, slavery and violent conflict have been happening for centuries. They also contend that there are huge issues of social inequality and social justice that drive these problems, which are arguably more important than declining wildlife.

Brashares doesn't argue either point but said: "There has never been more of this going on than there is now. If you want to understand poverty, look at how people eat."

For McCauley, the most important lessons of the research have been personal.

"I hope [the research] impacts how we form messages," he said. "We need to as ecologists tell more complete stories of these declines."